The Effect of Process Parameters on Microstructural Properties of Severe Plastically Deformed Dual Phase 600 Steel Via Friction Stir Processes


Aktarer S. M. , SEKBAN D. M. , KÜÇÜKÖMEROĞLU T.

13th Junior EUROMAT 2016, Lausanne, Switzerland, 10 - 14 July 2016, vol.1, no.1, pp.53

  • Publication Type: Conference Paper / Summary Text
  • Volume: 1
  • City: Lausanne
  • Country: Switzerland
  • Page Numbers: pp.53

Abstract

High strength, deep drawability and high strain hardenability are some of the well-known engineering propertiesof the dual phase (DP) steels. Therefore, so as to diminish the vehicle weight and enhance the car safety, these steels are extensivelyused in the automotive industry. In addition, attempts are still being made to

improve the formability and strength porperties of this steel in the automotive industry. Volume fraction, microstructural morphology, the grain size and the carbon content are the factors by which the mechanical properties of DP steels can be changed. Thus, some grain refinement and microstructural modification techniques depending on severe plastic deformation (SPD) have lately been

introduced to eliminate the obstacles of the traditional processes. One of the SPD techniques is Friction Stir Processing (FSP), a newly developed technique. In the is study, DP 600 steel with 1.5mm thickness was subjected to FSP, by using a WC tool consisting of a flat shoulder and having a diameter of 12 mm; and a conical of 20 o angle pin with a diameter and length of 5mm and 1.2mm, respectively. During the processing, tool was tilted 2o , and downforce of the tool was kept constant at 5kN. The experiments were carried out at three different tool rotation speed (1000,1250 and 1600 rpm) and three different processing speed (65, 115 and 170 mm/min). After FSP, islandsof martensite as the secondary phase in the microstructure have been broken and disturbed by the rotational pin. There has been a remarkable grain refinement in the microstructure of ferrite.